Help me troubleshoot this pack please. How are these voltages?

Batteries, Chargers, and Battery Management Systems.
999zip999   100 GW

100 GW
Posts: 9515
Joined: Jan 10 2010 1:40pm
Location: Dana Point So. Cal

Re: Help me troubleshoot this pack please. How are these voltages?

Post by 999zip999 » Mar 23 2020 7:24pm

https://images.app.goo.gl/AjF1zRK1BQgxYyNt9. Be yea cellog is discontinue. Una chargers is dead ?
https://www.rcnhobby.com/unrc-un-a6-plu ... arger.html
You should find it cheaper.

eikido   10 W

10 W
Posts: 73
Joined: May 08 2019 5:07am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by eikido » Apr 12 2020 2:49am

I'm having issues finding the bad cell(s).

Here is a video:
https://www.youtube.com/watch?v=pVJT2L6f1Vg

I load the battery pack and monitor two cell groups. The bad cell group 11 (which is actually group 3) and some random one.
It is very clear that cell group 3 (11) is going out of balance when loaded.

I harvested the cells and did a capacity test on all with my liitokala Lii-500s but couldn't notice something obvious.

I did discover one thing but could it be that cell?`

My Lii-500s can display the charge and discharge capacity:

Cell 1: Discharge: 2872 ; Charge: 2832
Cell 2: Discharge: 2890 ; Charge: 2741
Cell 3: Discharge: 2830 ; Charge: 2836
Cell 4: Discharge: 2903 ; Charge: 2910
Cell 5: Discharge: 2781 ; Charge: 2858
Cell 6: Discharge: 2695 ; Charge: 2955

Could it by any chance be an issue with cell 6?


Edit: I measured Cell 6, 3.2V, put it in the charger and set it to discharge at 500mA and it dropped very quickly (less than a minut) to 3.02v. After three minutes down to 2.9v. Took it out, measured about 3.05v, after 30 minutes, 3.15v.
Last edited by eikido on Apr 12 2020 4:10am, edited 1 time in total.

docware   1 kW

1 kW
Posts: 317
Joined: Sep 16 2018 5:36am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by docware » Apr 12 2020 4:03am

Eikido, it seems to me that your effort to build battery from noname chinese cells is wasting of money and time.

eikido   10 W

10 W
Posts: 73
Joined: May 08 2019 5:07am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by eikido » Apr 12 2020 4:11am

docware wrote:
Apr 12 2020 4:03am
Eikido, it seems to me that your effort to build battery from noname chinese cells is wasting of money and time.
I'm not building it, i'm troubleshooting it for a friend.
It's a great way to learn.
Everybody starts from 0.

docware   1 kW

1 kW
Posts: 317
Joined: Sep 16 2018 5:36am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by docware » Apr 12 2020 5:49am

Well, this lesson brings advice : don´t waste your time with noname chinese cells and throw them to the hazardous scrap.

eikido   10 W

10 W
Posts: 73
Joined: May 08 2019 5:07am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by eikido » Apr 12 2020 6:23am

docware wrote:
Apr 12 2020 5:49am
Well, this lesson brings advice : don´t waste your time with noname chinese cells and throw them to the hazardous scrap.

Are you in a bad mood?
Please don't take it out on me.

john61ct   100 GW

100 GW
Posts: 5623
Joined: Dec 18 2018 2:06pm

Re: Help me troubleshoot this pack please. How are these voltages?

Post by john61ct » Apr 12 2020 12:26pm

I do not perceive any hostility there.

He is giving you helpful advice.

But you can choose to delay following it, for the sake of your learning

eikido   10 W

10 W
Posts: 73
Joined: May 08 2019 5:07am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by eikido » Apr 12 2020 3:28pm

It's ok, i will try myself.
I'm not expecting any help, i only appreciate any help i get.
I'm learning and i think this is the best way to learn. I wouldn't do the same on a big pack with loads of MJ1's.

And sincpower is also not all that bad.
http://www.sincbattery.org/index.html

john61ct   100 GW

100 GW
Posts: 5623
Joined: Dec 18 2018 2:06pm

Re: Help me troubleshoot this pack please. How are these voltages?

Post by john61ct » Apr 12 2020 6:07pm


eikido wrote:And sincpower is also not all that bad.
http://www.sincbattery.org/index.html
What evidence do you have for that statement?


eikido   10 W

10 W
Posts: 73
Joined: May 08 2019 5:07am

Re: Help me troubleshoot this pack please. How are these voltages?

Post by eikido » Apr 13 2020 2:35am

john61ct wrote:
Apr 12 2020 6:07pm
eikido wrote:And sincpower is also not all that bad.
http://www.sincbattery.org/index.html
What evidence do you have for that statement?
They are in many ebikes and scooters and have been around for many years and they don't try to hide their brand like other fake chinese factories.
But yes, i haven't seen any proper tests on those cells.

Post Reply